Correct Option: C

V_A = V₁
V_B = V₂
due to virtual ground. Let us assume that current I is flowing in the loop given below:

=	VA – VB
	2 kΩ

By applying KVL in the loop.
V_o – 6I – 2 I – 4 I = 0
or V_o = 12 I

Vo = 12.	(VA – VB)
	2

or Vo =	12	. (V1 – V2)
	2

or	Vo	= 6 = Avd
	V1 – V2

Hence alternative (C) is the correct choice.